Flagging Inland Data - Rolling SD

Inland Parameters: Explore Thresholds

Summary

CMAR has collected data on several inland bodies of freshwater in Nova Scotia through the wild Atlantic salmon river monitoring project. In addition, CMAR has data collected on several freshwater lakes (e.g. Piper Lake), which is currently published through the Water Quality branch of the Coastal Monitoring Program.

CMAR intends to process and republish all inland data under a new “Inland” branch of the Coastal Monitoring Program. Data will be processed in a similar manner to the water quality data, and data flags will be applied using the qaqcmar package.

It is suspected that sensors on some rivers were out of the water for some period of time during the deployment. Data flagging efforts will flag data for periods of time sensors were suspected to be exposed. During the periods in which sensors were exposed to air, recorded temperatures fluctuate more quickly than when sensors are submerged.

The purpose of this document is to help CMAR determine appropriate data flagging tests and thresholds for freshwater (inland) data. We do not currently have enough freshwater data to conduct as thorough an analysis as was done on the saltwater water quality data to develop tests and thresholds, so thresholds may be picked in more subjective ways.

Waterbodies in dataset:
[1] "Gold River"         "LaHave River"       "Liscomb River"     
[4] "Mersey River"       "Musquodoboit River" "Roseway River"     
[7] "Round Hill River"   "Salmon River"       "Tusket River"      
Stations in dataset:
 [1] "Gold 2"         "LaHave 1"       "LaHave 2"       "LaHave 3"      
 [5] "Liscomb 1"      "Liscomb 2"      "Mersey 2"       "Musquodoboit 1"
 [9] "Musquodoboit 2" "Musquodoboit 3" "Roseway 1"      "Roseway 2"     
[13] "Round Hill 1"   "Round Hill 2"   "Round Hill 3"   "Salmon 1"      
[17] "Salmon 2"       "Tusket 1"       "Tusket 2"       "Tusket 3"      
Stations which may have experienced air exposure:
  • Liscomb 1
  • Liscomb 2
  • LaHave 2
  • Mersey 2
  • Tusket 3
  • Possibly Musquodoboit 1 and 2

Station Locations

Approximate location of stations included in analysis.

Plot all Station Data

Plot Cleaned Station Data

Suspected outliers have been removed from the following datasets:

  • Liscomb 1
  • Liscomb 2
  • LaHave 2
  • Mersey 2
  • Tusket 3

Distribution plots

Distribution of sd_roll

Distribution of temperature observations by station (binwidth = 0.25 degree c).

Distribution all

Distribution of temperature observations (binwidth = 0.25 degree c).

Apply Thresholds

Visualize flagged data

Mean_sd

Quartile

Quartile Pooled 0.95

Quartile Pooled 0.97

Quartile Pooled 0.99

Quartile Pooled 0.997

Apply test

Due to the right-skew of the sd_roll distribution plots, the quantile method was used to establish thresholds. Because the overall distribution of the data was relatively the same for each station, all station data was pooled before determining a threshold and applying the test.

Plot Flagged/Cleaned Station Data